I think it's been no secret it's been a couple tough years here at WJ. Some I'm sure left for faster financial gain, some left for getting a base in their desired city faster (ie Vancouver). Some left in hopes of a quick upgrade and some left because their third wife was leaving them with $200/month in the bank after all the support payments - so off to China they went.
A friend from Winnipeg summarized it great one time - you are standing in the grocery line - the line to your right started moving faster (lets just call it AC for argument sake) - so you pop over to that line. Some get through fast and then the guy in front of you starts digging for change and you wonder if you now made the right move because it started to really slow down....
I think it's in our DNA to move and try and get ahead, especially when you are junior (which is the majority of our attrition). Wayyy back too, I thought I would never see a left seat at Air Ontario when I was there - The CDN merge, flow to AC stopped etc....I was looking at a mountain of guys ahead of me - so I popped over to WestJet, now look at Jazz! That was almost 19 years ago...still love this place, missed the big payout but love the socialized bidding and of course all the peers etc...each place has it's merits. It's still a great place to work and will continue to improve imho. The best part is - I get to go fly a caravan in the summer on amphibs
So, to answer your question - I really can't - if that makes sense. Everyone has their own reasons....I think you will always see guys just trying to get ahead and make the best anticipated choice. Some that have gone are happy with their decision, some have tried to come back and some have said there isn't much difference. At the end of the day it's what you make of it. Do your homework and hopefully make a choice that you would be happy with should the music ever stop.
As for the numbers - I think we were just over 2% YTD including some retirements and other reasons (the last time I checked based off almost 1600 pilots). Sorry - I can't recall the previous years. I do think it was less though.
We have a crazy year coming up for recruiting (classes of 16 and 20), the biggest I've ever seen here. Growth, contract, trip and duty, reserve, augmentation on the wide body, retirements etc all contributing. Again, it's a great time to be a pilot. Despite what or how the forum reads there are a lot of good companies here in Canada. Sometimes we forget how fortunate we are here in this country. BTW Trudeau loves our tax rate too...ugggggh.